Project Summary ODMR Technologies, Inc. and Prof. Victor Acosta's group at University of New Mexico (UNM) are developing a diamond-chip platform capable of ?direct magnetic characterization of individual nanoparticles for optimized diagnostic imaging. ?Our team is a spinoff from academic collaborations in the emerging field of diamond photonic sensors; a field we helped create nearly a decade ago. After years of refining this technology in the lab, we are ready to commercialize our most promising devices. Magnetic nanoparticle (MNP) research has seen a flurry of activity in recent years, owing to potential applications in catalysis, data storage, biosensing, medical imaging, including magnetic resonance imaging (MRI), magnetic particle imaging, and magnetic relaxation imaging (MRX), drug delivery, and hyperthermia treatment. These applications would benefit from using MNPs with highly uniform composition, size, shape, and magnetic properties. However, MNP production is notoriously plagued by reproducibility problems, inaccurate specifications, and a lack of common practices. Tools for quantitative magnetic measurements of individual nanoparticles are not commercially available. Advanced characterization tools are often either inaccessible (due to cost and maintenance) or simply do not exist. If the cost, accuracy, versatility, and throughput of proposed instruments can be improved they could have a dramatic impact on MNP applications. Developing a diamond-chip platform for high-sensitivity, parallel characterization of individual MNPs is the focus of this proposal. The magnetic hysteresis and relaxation properties of thousands of individual MNPs will be simultaneously characterized using a magnetic microscope based on nitrogen-vacancy (NV) color centers doped near the surface of a diamond chip. The magnetic measurements for each individual MNP will be correlated with its composition and morphology, as determined by high-resolution transmission electron microscopy. Unlike existing techniques, the proposed platform works at ambient conditions and offers high throughput (>1000 individual particles per 10 min). To date, we have built a setup designed for imaging particles with ~100 nm core diameters. In the proposed research plan, we will optimize the benchtop prototype for ~20 nm sized particles. Our goal is to build a benchtop magnetic imaging apparatus with 1 T sensitivity in (400 nm)?2 resolved pixels, 0-200 mT tuning range, and >1000 frames per second. Next, we will characterize the magnetic dynamics of superparamagnetic iron oxide nanoparticles (SPIONs) with 15-22 nm diameter, with a goal of improving their applicability in biomedicine. We will obtain hysteresis curves and magnetization decay curves with record throughput. Correlative TEM and magnetic images of numerous individual SPIONs will be obtained, and may finally unambiguously elucidate the relationship between SPION size, shape, magnetization relaxation, and hysteresis curve properties.